1. Field of the Invention
The present invention relates to an image forming device and the like capable of printing on both sides of a sheet, and more particularly to an image forming device and the like capable of satisfactorily printing on both sides of a sheet when performing manual two-sided printing.
2. Description of the Related Art
Printers, photocopy machines, and other image forming devices have for some time performing printing on both sides of sheets, in the interest of conserving paper and for other reasons. This two-sided printing includes both so-called automated two-sided printing, in which the image forming device performs automated handling of the sheet, and so-called manual two-sided printing, in which a human again sets a sheet which has been printed on one side in the image forming device.
In this two-sided printing, after printing on one side of the sheet, printing is again performed on the other side of the sheet, so that in order to print on the other side, print processing is performed on a sheet one side of which has already been printed onto. Hence in order to perform satisfactory printing onto both sides in two-sided printing, it is desirable that the conditions for image forming be changed when printing onto one side of a sheet onto which nothing has yet been printed, and when printing onto the other side.
For example, in Japanese Patent Publication No. 3109698, it is proposed that in light of the above problem, the image forming conditions be altered when printing the first side and the second side in manual two-sided printing.
However, in the above patent reference there is no indication of the specific timing for changing the image forming conditions, and in the prior art it has not always been clear with what timing the image forming conditions should be changed when performing manual two-sided printing. And during manual two-sided printing, user operations such as manually setting the sheet are necessary when processing the second side (rear side), so that printing control for the second side (rear side) which takes into account the timing relative to user operation is necessary.